1. Field
The present disclosure relates to a transparent heat-insulating material including polymer capsules and a method for producing the same.
2. Description of the Related Art
Many attempts have been made to save cost required for cooling and heating of buildings, particularly glass-walled buildings constructed largely in recent years.
Energy consumption in glass-walled buildings reaches 24% of the total energy consumption, and heat loss through windows occupies 30% of the total energy consumption on average and at least 7% of the total energy loss. Since the heat transfer coefficient of a window is at least 5 times higher than that of the outer wall or roof of a building, such a window is a main cause of heat loss. Moreover, in summer, solar radiation transmits through a window, which is one of the causes of cooling load, resulting in 66% of cooling load. In winter, during indoor heating, heat escapes through a window, which is one of the causes of heating load, and heat loss through a window reaches for 92% of heating load.
Therefore, many attentions have been given to improvement in the heat-shielding performance of a building window system. As a solution therefor, according to the related art, there has been suggested a method for connecting an inner part of a frame and an outer part thereof to each other with a non-metallic heat-insulating material having low heat conductivity to accomplish interruption of heat flow. In addition, air caps have been used to prevent conduction of cold air from outside through a glass window.
Further, some efforts have been made to increase heat-insulating quality through a temperature difference by introducing inert filler gas, such as air, argon or krypton, directly to pair glass.
However, according to the observation by the present inventors, the use of air caps or direct introduction of inert filler gas according to the related art is problematic in that it is difficult to ensure related techniques, such as durability upon sealing of such filler gas, gas mixing processes or control of mixing ratio, and further in that complicated processes are required and cost-efficiency is low.
Meanwhile, according to the related art (Korean Patent Publication No. 0870908), a method for producing a film-like glass heat-insulating material is disclosed, and the method includes carrying out extrusion molding of a blend of a polyvinyl chloride resin, microsilica capsules and a plasticizing agent.
However, according to the observation by the present inventors, the method is problematic in that it is not possible to control a size of microsilica capsules that affect transparency and heat-insulating property of glass, and thus it is difficult to control the transparency and heat-insulating property. Moreover, the method involves complicated processes.